It has long been known that oximes can be converted to the corresponding amides using acid catalysts, for example sulfuric acid; this conversion is known as the Beckman rearrangement. One major commercial application of the Beckman rearrangement is the conversion of cyclohexanone oxime to caprolactam.
Caprolactam is a large volume commodity chemical used as a monomer in the production of nylon 66. Annual worldwide production of caprolactam stands at about four billion pounds with U.S. production being close to 800 million pounds. At present, the major commercial process for the production of caprolactam is the sulfuric acid catalyzed Beckman rearrangement of cyclohexanone oxime. A major drawback of using sulfuric acid to catalyze the rearrangement reaction is that a large amount of ammonium sulfate is produced as a by-product; in commercial production, the rearrangement produces as much as 1.5 parts by weight of ammonium sulfate for each part by weight of caprolactam.
The most common commercial process for the production of cyclohexanone oxime also generates large amounts of ammonium sulfate by-product but new technology is available which eliminates ammonium sulfate production during the synthesis of cyclohexanone oxime. Thus, elimination of ammonium sulfate production in the Beckman rearrangement step would represent a dramatic improvement in commercial caprolactam production, particularly when coupled with the production of cyclohexanone oxime by a process which does not produce ammonium sulfate, since the complete elimination of ammonium sulfate production from both steps of the caprolactam synthesis would eliminate the need for equipment to handle the ammonium sulfate by-product. Even if the conventional method were used to produce the cyclohexanone oxime, elimination of ammonium sulfate production during the rearrangement to caprolactam would greatly reduce the amount of ammonium sulfate which has to be handled.
Thus, probably the most economical process which could be envisaged at present for the production of caprolactam is an ammonium sulfate free process for the production of cyclohexanone oxime coupled with a new catalytic Beckman rearrangement step that completely eliminates the ammonium sulfate by-product.
Efforts have previously been made to develop a gas phase, heterogeneous, ammonium sulfate free process for caprolactam production. Several zeolite molecular sieve systems are known to catalyze the Beckman rearrangement. For example, U.S. Pat. No. 4,359,421 issued Nov. 16, 1982 to Bell and Chang (assigned to Mobil Oil Corporation) describes the use of the zeolite known commercially as ZSM-5 as a catalyst for the conversion of cyclohexanone oxime to caprolactam, but gives no data concerning the selectivity of the reaction to caprolactam. The following publications describe the use of zeolites as catalysts for the production of caprolactam from cyclohexanone oxime; the zeolites used include X and Y zeolites and some of the natural zeolites, often in combination with silica alumina or borates, and in general the selectivity to caprolactam is rather low:
Loseva, L. P.; Bel'skaya, R. I., Dokl. Akad. Nauk BSSR, 1984, 28(11), 1013-15;
Shirinskaya, L. P.; Malashevich, L. N.; Komarov, V. S.; Bolotnikova, E. V.; Pis'mennaya, A. V., Dokl. Akad. Nauk BSSR, 1984, 28(7), 628-31;
Shirinskaya, L. P.; Komarov, V. S.; Loseva, L. P.; Bel'skaya, R. I., Vestsi Akad. Nauk BSSR, Ser. Khim. Navuk, 1984, 1984(2), 23-7;
Shirinskaya, L. P.; Stepanova, E. A.; Komarov, V. S., Dokl. Akad. Nauk BSSR, 1983, 27(8), 723-6;
Shirinskaya, L. P.; Komarov, V. S.; Stepanova, E. A., Dokl. Akad. Nauk BSSR, 1983, 27(7), 638-40;
Shirinskaya, L. P.; Malashevich, L. N.; Komarov, V. S.; Bolotnikova, E. V.; Pis'mennaya, A. V., Dokl. Akad. Nauk BSSR, 1984, 28(9), 814-16;
Loseva, L. P.; Shirinskaya, L. P.; Bel'skaya, R. I.; Komarov, V. S., Dokl. Akad. Nauk BSSR, 1982, (1), 47-9;
Shirinskaya, L. P.; Komarov, V. S.; Loseva, L. P.; Bel'skaya, R. I., Dokl. Akad. Nauk BSSR, 1980, (4), 348-50;
Mobil Oil Corporation, European Patent Application No. 82300133.4 (Publication No. 56698), published July 28, 1982;
Shirinskaya, L. P.; Komarov, V. S.; Loseva, L. P.; Bel'skaya, R. I., U.S.S.R. Pat. No. 891,146, issued Jan. 13, 1982;
Shirinskaya, L. P.; Komarov, V. S.; Loseva, L. P.; Bel'skaya, R. I., U.S.S.R. Pat. No. 755,295, issued Aug. 15, 1980; and
Butler, J. D.; Poles, T, C., J. Chem. Soc., Perkin Trans. II, 1973, 41.
Attempts have also been made to use other heterogeneous catalysts in a gas phase process for the conversion of cyclohexanone oxime to caprolactam. Such heterogeneous catalysts have included
(a) borates and boron phosphates; see:
Bayer AG., West German Offenlegungsschrift No. 1670816, published Sept. 2, 1976; PA1 Badische Anilin- & Soda-Fabrik AG., West German Offenlegungsschrift No. 2120205, published Nov. 2, 1972; PA1 Badische Anilin- & Soda-Fabrik AG., West German Offenlegungsschrift No. 2837793, published Mar. 13, 1980; PA1 Badische Anilin- & Soda-Fabrik AG., West German Offenlegungsschrift No. 2641408, published Mar. 16, 1978; PA1 Badische Anilin- & Soda-Fabrik AG., West German Offenlegungsschrift No. 2055621, published May 18, 1972; PA1 Immel, O; Schwarz, H. H., U.S. Pat. No. 3,574,193, issued Apr. 6, 1971 (assigned to Farbenfabriken Bayer); PA1 Immel, O; Schwarz, H.-H.; Schnell, H., U.S. Pat. No. 3,586,668, issued June 22, 1971 (assigned to Farbenfabriken Bayer); PA1 Irnich, R., U.S. Pat. No. 3,154,539, issued Oct. 27, 1964 (assigned to Badische Anilin- & Soda-Fabrik AG.); PA1 Izumi, Y.; Sato, S.; Urabe, K., Chem. Lett., 1983, 1649; PA1 Stamicarbon B. V., Netherlands Patent Application No. 8204837, published July 1984; PA1 Farbenfabriken Bayer, French Patent Application No. 69 28956 (Publication No. 2016341), published May 8, 1970; PA1 Gorshkov, V. I.; Badrian, A. S.; Vainer, S. Ya.; Surkova, T. M.; Shestakova, O. N., Tr. N.-i. i proekt. in-ta azot. prom-sti i produktov organ. sinteza, 1973, (22), 20-5; PA1 Gabalov, E. V.; Pechkovskii, V. V.; Loseva, L. P.; Bel'skaya, R. I., Vestsi Akad. Navuk BSSR, Ser. Khim. Navuk., 1982, 4, 114-15; PA1 Gorshkov, V. I.; Badrian, A. S.; Gazanchiyants, M. G.; Dolokhov, D. M.; Dmitrieva, N. A., U.S.S.R. Pat. No. 635,095, issued Nov. 30, 1978; PA1 Kurkin, G. A.; Levina, O. V.; Badrian, A. S.; Gorshkov, V. I.; Baeva, V. P.; Surkova, T. M.; Vainer, S. Ya., Tr. Gos. Nauchno-Issled. Proektn. Inst. Azotn. Prom-sti. Prod. Org. Sint., 1974, 27, 9-16; and PA1 Sikharulidze, N. G.; Grdzelidze, I. M.; Bakhtadze, E. I.; Gulua, L. P.; Khmelidze, R. V., U.S.S.R. Pat. No. 301,063, issued June 4, 1971. PA1 Mitsubishi Chemical Industries Co., Ltd., Japanese Pat. No. 48-10478 (Application No. 73-10478), issued Apr. 3, 1973; PA1 Teijin Ltd., Japanese Pat. No. 53-9785 (Application No. 78-9785), issued Jan. 28, 1978; PA1 Asahi Chemical Industry Co., Ltd., Japanese Pat. No. 48-12754 (Application No. 73-12754), issued Apr. 23, 1973; PA1 Toray Industries, Inc., Japanese Patent 47-8048 (Application No. 72-8048), issued Mar. 8, 1972; PA1 Toyo Rayon Co., Ltd., Japanese Pat. No. 44-27647 (Application No. 69-27647), issued Nov. 17, 1969; PA1 Yashima, Tatsuaki; Horie, Shigeru; Saito, Sumiko; Hara, Nobuyoshi, Nippon Kagaku Kaishi, 1977, (1), 77-81; and PA1 Matsuda, Toshio; Motohashi, Chuichi; Takahashi, Kenji; Tsuchiya, Shiro; Takata, Yoshiyuki, Hokkaido Daigaku Kogakubu Kenkyu Hokoku, 1970, (55), 129-40; PA1 Costa, A.; Esteban, S.; Marinas, J. M.; Perez-Ossorio, R., An. Quim., 1977, 73(12), 1529-31; PA1 Costa, A.; Deya, P. M.; Sinisterra, J. V.; Marinas, J. M., An. Quim., Ser. C, 1982, 78(1), 43-7; PA1 Esteban, Soledad; Marinas, Jose M., Afinidad, 1981, 38(371), 19-22; and PA1 Costa, A.; Deya+, P. M.; Sinisterra, J. V.; Marinas, J. M., Can. J. Chem., 1980, 58, 1266; and PA1 Ciminao, G.; Vitarelli, P.; Alibrandi, B.; Caristi, C.; Galvagno, S., React. Kinet. Catal. Lett., 1982, 21(4), 467.
(b) metal oxides or combined metal oxides; see:
(c) amorphous aluminum phosphates; see:
(d) fluorinated alumina; see:
In spite of the potential benefits which could be afforded by a heterogeneous, gas phase Beckman rearrangement for caprolactam production, and despite the large amount of work done to develop such a gas phase process, as evidenced by the numerous literature references given above, at present no such heterogeneous, gas phase processes are being run commercially. The failure to develop such a commercially-viable process may possibly be due to difficulties with the stability and/or selectivity of the prior art catalysts.
Although the use of molecular sieves could theoretically alleviate some of the difficulties with other heterogeneous catalysts, hitherto attempts to use zeolite molecular sieves as catalysts for the Beckman rearrangement have resulted in many undesired side reactions, and consequently in low selectivities.
It has now been discovered that the use of certain non-zeolitic molecular sieves as catalysts in the Beckman rearrangement offers greater selectivities to the desired amides than has been achieved in prior art molecular sieve catalyzed processes, and that these high selectivities can be maintained at high oxime conversion.